Recruitment continues of a population of adult patients with moderate to severe hypertension. A complete ophthalmologic examination including fundus photography and fluorescein angiography is performed. The retinopathy is classified following a new scheme developed by the investigators. Every 3-6 months, the retinopathy is reassessed. The success of antihypertensive therapy and any systemic complications of the hypertension are recorded. In this manner, correlations will be made between the fundus changes and the blood pressure, and complications of the hypertension. Vitreous fluorophotometry is also being performed on some patients and, in the future, a television ophthalmoscopy system will be used to record retinal blood flow rates, transit times and oximetry data on hypertensive patients before and after antihypertensive therapy.